chapter 2-1chemistry 120 online la tech chapter 2 measurements in chemistry

Chapter 2-1Chemistry 120 Online LA Tech

Chapter 2

Measurements In Chemistry


© Richard Hamilton Smith/Corbis Outline

Measurements are not exact

→ Measurements can never be exact; there is always

some uncertainty.


Metric system units are becoming increasingly evident on highway signs.

Metric System


¬ Table 2.1

Metric Prefixes


→ Fig. 2.2 Comparisons of the base metric system units of length, mass, and volume with common objects.

Metric System Base Units

E.R. Degginger


Volume Unites (cm3, L and mL)

← Fig. 2.3

A cube 10 cm on a side is equal to 1 L; a cube 1 cm on a side is equal to 1 mL.


Solution Concentration Units

The use of the concentration unit milligrams per deciliteris common in clinical laboratory reports dealing with the composition of human body fluids.


The scale on a measuring device determines the magnitude of the uncertainty for the recorded measurement.

Uncertainty of Measurements


Significant Figures in Measurements


The digital readout on an electronic calculator usually shows more digits than are needed.

Rounding off from Calculator Answer


Unit Conversions

It is experimentally determined that 1 inch equals 2.54 cm, or 1 cm equals 0.394 inch


Unit Conversion Factors

← Table 2.2


Common Conversion Factors

®


Densities and Masses

Both of these items have a mass of 23 grams, but they have very different volumes; therefore, their densities are different as well.


Properties of Gases, Liquids and Solids

→ Table 2.3


Why the Coin floats on Mercury?

← Fig. 2.9

The penny is less dense than the mercury it floats on.


Measurements of Body Density


Specific Heat of Substances

→ Table 2.4


Temperature Scales

→ Fig 2.10 The relationships among the Celsius, Kelvin, and Fahrenheit temperature scales are determined by the degree sizes and the reference point values.

chapter 2-1chemistry 120 online la tech chapter 2 measurements in chemistry

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